Influence of Meal Timing and Sleep Variability on Macronutrient Intake and Body Composition in College Undergraduates

 描述(申请人提供)：在整个发达国家，体重增加和肥胖已经达到了令人震惊的水平。超过30%的美国人肥胖，全球有14亿成年人超重。肥胖是许多代谢性疾病的风险因素，每年在美国造成约1470亿美元的医疗费用。肥胖率的最大增幅出现在大学年龄人口中，这个年龄是建立长期健康行为的关键发展时期。夜间进食和可变的睡眠时间是导致体重增加和肥胖的新的潜在风险因素，但人们对这些风险因素如何影响大学年龄人口的体重和肥胖知之甚少。我们最近发现，大学生在2000年后进餐的次数与身体脂肪相对于体重的比例更高有关。然而，关于饮食时间与昼夜生理和睡眠-觉醒行为之间的关系还需要更多的细节，因为：(I)与老年人相比，大学生的昼夜节律延迟，因此2000h可能不是“昼夜”(即褪黑激素升高的时候)；(Ii)一天中特定时间的膳食组成可能会不同地影响身体组成；以及(Iii)可变的睡眠-唤醒时间可能会影响食物的摄入时间。因此，我们提出了一项实验，以确定大学生的饮食和睡眠-醒来时间变异性与体重、身体组成和饮食组成的关系。这项研究将是对美国国立卫生研究院R01项目的补充，该项目是关于社交网络对大学生睡眠的影响。在这项研究中，每个学生在校期间参加为期一个月的研究：(I)每天完成两次关于睡眠-醒来模式的在线日记；(Ii)佩戴监测睡眠和清醒情况的传感器；(Iii)允许他们的手机上的应用程序跟踪电话和互联网的使用情况；以及(Iv)在我们的设施中过夜以评估褪黑激素的开始(一种昼夜节律阶段的标志，以及昼夜节律系统开始促进睡眠的时间)。对于这一补充，我们还将使用带有时间戳的手机食物日记跟踪7天的食物摄入时间和含量，并记录他们的体重和身体成分(体脂百分比)。将使用每日在线睡眠-唤醒日记和可穿戴传感器来评估睡眠变异性，这些传感器可以测量每天的睡眠时间和持续时间。这项拟议工作的结果将使我们能够量化在不适当的昼夜节律时间进食、睡眠-醒来时间变异性、体重、身体成分和膳食成分之间的关系。确定潜在的可改变的行为(例如，饮食和睡眠的时间安排)以降低这一人群的体重水平，对于制定基于研究的战略，以减少成年期间的负担和高疾病成本至关重要。这一结果将提供有关昼夜节律、睡眠-觉醒行为和新陈代谢之间关系的更多信息。这些知识可用于公共卫生论坛，包括关于食物时机及其对身体成分影响的教育活动。

 DESCRIPTION (provided by applicant): Weight gain and obesity have reached alarming levels throughout the developed world. Over 30% of Americans are obese and 1.4 billion adults worldwide are overweight. Obesity is a risk factor for numerous metabolic diseases and accounts for ~$147 billion in health care costs each year in the United States. The greatest increase in prevalence of obesity rates occurs in the college-aged population, an age that is a critical developmental time period for establishing long-term health behaviors. Eating during the night and variable sleep-wake timing are novel potential risk factors for weight gain and obesity, yet little is known about how these risk factors influence weight and obesity in the college-aged population. We have recently found that the number of meals college students consume after 2000h is associated with a higher percentage of body fat relative to weight. However, more detail is needed on the relationship between the timing of meals with circadian physiology and sleep-wake behaviors as: (i) the circadian phase in college students is delayed as compared to older populations and thus 2000h may not be the "circadian" night (i.e., when melatonin is elevated); (ii) composition of meals at specific times of the day could differently affect body composition; and (iii) variable sleep-wake timing may influence the timing of food intake. We therefore propose an experiment to identify the association of both meal and sleep-wake timing variability with weight, body composition, and meal composition in college undergraduates. This study will be a supplement to a currently funded NIH R01 project on the effects of social networks on sleep in college students. For that study, each student participates for 1-month while at school by: (i) completing online diaries twice daily about sleep-wake patterns; (ii) wearing sensors that monitor sleep and wakefulness; (iii) allowing an application on their mobile phone to track phone and internet usage; and (iv) staying overnight at our facility to assess melatonin onset (a marker of circadian phase and the time at which the circadian system begins to promote sleep). For this supplement, we will also track the timing and content of food consumed using a time-stamped mobile phone food diary for a 7-day period and record their weight and body composition (percent body fat). Sleep variability will be assessed using the daily online sleep-wake diaries and wearable sensors that measure daily sleep timing and duration. The results from the proposed work will allow us to quantify relationships among eating at inappropriate circadian times, sleep-wake timing variability, weight, body composition, and meal composition. Identifying potential modifiable behaviors (e.g., timing of meals and sleep) to reduce weight levels in this population is crucial for developing research based strategies for decreasing the burdens and high cost of disease during adulthood. The results will provide additional information about the relationships between circadian rhythms, sleep-wake behavior, and metabolism. The knowledge can be utilized in public health forums, including educational campaigns about food timing and its effects on body composition.